KR20070115716A - Oscillating type compressor - Google Patents

Abstract

An oscillating type compressor is provided to prevent concentration of wear on a lip ring by differentiating loaded area of the lip ring using a motor rotated forward and reversely, thereby elongating service life of a seal member. An oscillating type compressor comprises a cylinder(7), a piston(16), an annular seal member(22), and a controller. The piston is connected to an output shaft of a motor, defining a compression chamber within the cylinder, and reciprocates in the cylinder while oscillating. The annular seal member is installed on the circumference of the piston to seal between the piston and the cylinder. The controller converts the driving of the motor between a forward rotation for compressing and a reverse rotation for compressing.

Description

Oscillating compressor {OSCILLATING TYPE COMPRESSOR}

1 is an overall configuration diagram showing a rocking type compressor according to a first embodiment of the present invention.

2 is a longitudinal sectional view showing the electric motor and the compression unit in FIG.

3 is a cross-sectional view of the compression unit viewed in the direction of arrow III-III in FIG. 2;

4 is a circuit diagram showing a switching circuit in FIG.

5 is a flowchart showing pressure type operation control of a rocking compressor.

6 is a flowchart showing a compression operation process in FIG. 5;

FIG. 7 is a flowchart showing the continuous operation process shown in FIG. 5; FIG.

Fig. 8 is a sectional view seen from the same position as in Fig. 3 showing the suction stroke of the compression section when the electric motor is rotated forward.

9 is a sectional view seen from the same position as in FIG. 3 showing the compression stroke of the compression section when the electric motor is rotated forward.

FIG. 10 is an enlarged sectional view of a main part showing an enlarged portion of the load side of the lip ring in FIG. 9; FIG.

Fig. 11 is a sectional view seen from the same position as in Fig. 3 showing the suction stroke of the compression section when the electric motor is rotated in reverse.

12 is a sectional view seen from the same position as in FIG. 3 showing the compression stroke of the compression section when the electric motor is rotated in reverse. FIG.

FIG. 13 is an enlarged sectional view of a main part showing an enlarged portion of a load side of the lip ring in FIG. 12; FIG.

Fig. 14 is a characteristic diagram showing time changes in pressure, rotational speed, and rotational direction when intermittent operation is performed using the rocking type compressor according to the first embodiment.

Fig. 15 is a characteristic diagram showing time changes in pressure, rotational speed, and rotational direction when continuous operation is performed using the oscillating compressor according to the first embodiment.

Fig. 16 is a circuit diagram showing a switching circuit of the oscillating compressor according to the second embodiment.

Fig. 17 is a circuit diagram showing a switching circuit of the oscillating compressor according to the third embodiment.

Fig. 18 is a characteristic diagram showing time changes in pressure, rotational speed, and rotational direction when intermittent operation is performed using the rocking type compressor according to the third embodiment.

Fig. 19 is a sectional view of the same position as in Fig. 3 showing a rocking compressor according to a modification of the present invention.

<Explanation of symbols for the main parts of the drawings>

3, 31: electric motor

3A, 31A: Output Shaft

5: crankshaft

6: compression section

7: cylinder

16: piston

17: compression chamber

22: lip ring (seal member)

23: tank

24: pressure sensor

26: timer

27, 34, 42: switching circuit

28, 35, 43: control circuit (control means)

The present invention relates to a rocking compressor suitable for use in compressing a fluid such as air.

BACKGROUND ART Generally, as an oilless reciprocating compressor that compresses air or the like, a swing type compressor having a swing piston reciprocating while swinging in a cylinder is known (see Patent Document 1, for example). This oscillating compressor has a structure in which a piston is connected to a crankshaft and the crankshaft is rotationally driven using a motor. Moreover, the lip ring as a sealing member is attached to the outer peripheral side of a piston.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-161260

By the way, in the above-described rocking type compressor according to the related art, when the piston swings and reciprocates in the cylinder, only one point located on the load side during the compression stroke of the lip ring full circumference is strongly pressed against the inner circumferential surface of the cylinder and is worn out. .

That is, the pressure in the compression chamber is increased during the compression stroke in which the piston moves from the bottom dead center to the top dead center, and a large load acts on the piston and the lip ring. Moreover, the site side with a large displacement until reaching top dead center in a compression stroke among both ends of a piston swing direction becomes a load side to which a larger load acts. For this reason, uneven wear occurs in the site | part of this load side in a lip ring. In particular, during continuous operation of the compressor, the cylinder and the lip ring are brought to a high temperature state by the heat of compression, frictional heat, etc. from the compression chamber, so that wear of the lip ring is easily promoted.

As a result, in other parts of the lip ring, even though only about 30% of the thickness is worn out, there is a problem in that the sealing at the one point becomes impossible to seal. The lip ring is also fixedly attached to the disc's disc so that air does not leak from the compression chamber. For this reason, when a swing-type compressor is operated, abrasion occurs by concentrating on one point of the lip part located in the swinging direction of the piston, so that the life of the lip ring depends on the wear of this one point.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a rocking type compressor which can extend the life of a seal member by dispersing wear generated in the seal member.

The invention of claim 1 is connected to the cylinder, the output shaft of the motor and reciprocates while oscillating in the cylinder, and is provided on the outer circumferential side of the piston to seal the compression chamber in the cylinder, and seals between the piston and the cylinder. In the rocking type compressor comprising an annular seal member and a control means for controlling the driving of the motor, the control means is a compression operation by rotating the output shaft of the motor forward and compression, It is characterized by being comprised switchable.

In the invention of claim 2, the control means is configured to switch the rotational direction of the motor output shaft when starting the motor next time.

In the invention of claim 3, the control means is configured to switch the rotational direction of the motor output shaft when the motor is continuously driven for a predetermined time.

In the invention of claim 4, the control means is configured to switch with a predetermined rest time when switching the rotational direction of the motor output shaft.

Hereinafter, a rocking compressor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, Figs. 1 to 15 show a first embodiment of the present invention. In FIG. 2, 1 has shown the crankcase of the oscillating compressor. This crankcase 1 partitions the crankcase 2 therein, and as shown in Figs. 2 and 3, the cylindrical case portion 1A with its axis in the horizontal direction, and the cylindrical case portion 1A. It is comprised substantially by the cylinder attachment sheet | seat 1B etc. provided in the upper side of ().

3 is an electric motor attached to the crankcase 1, and this electric motor 3 is comprised by the three-phase induction motor, for example, and has the output shaft 3A which can be rotated forward or reverse. In addition, a cooling fan 4 is attached to the tip of the output shaft 3A of the electric motor 3. Thereby, the cooling fan 4 rotates with the output shaft 3A, and supplies cooling wind toward the cylinder 7 etc. which are mentioned later through the crank chamber 2. As shown in FIG. And the drive of the electric motor 3 is controlled using the control circuit 28 mentioned later.

5 is a crankshaft provided in the crankcase 2 of the crankcase 1, This crankshaft 5 is supported by the crankcase 1 so that rotation is possible. In addition, a balance weight 5A is integrally provided on the crankshaft 5. And the crankshaft 5 is connected to the output shaft 3A of the electric motor 3, and rotates with the output shaft 3A.

6 is a compression part driven by the electric motor 3, and this compression part 6 is comprised by the cylinder 7, the cylinder head 8, the piston 16, etc. which are mentioned later. The compression unit 6 sucks external air and discharges compressed air.

7 is a cylindrical cylinder affixed on the cylinder attachment sheet 1B of the crankcase 1, and this cylinder 7 is a lip ring whose base end side is opened into the crank chamber 2 and whose inner peripheral surface 7A is described later. It is a sliding movement surface of (22). In addition, a cylinder head 8 is mounted on the front end side of the cylinder 7, and in the cylinder head 8, as shown in FIG. 3, a suction chamber 9 which sucks outside air through the suction port 9A and The discharge chamber 10 which discharges compressed air through the discharge port 10A is partitioned.

11 is a valve seat plate inserted between the cylinder 7 and the cylinder head 8, and 11 A of suction holes which communicate the suction chamber 9 and the compression chamber 17 mentioned later to this valve seat plate 11. And a discharge hole 11B for communicating the discharge chamber 10 and the compression chamber 17 with each other. In addition, an intake valve 12 and a discharge valve 13 as reed valves are attached to the valve seat plate 11, and the intake valve 12 and the discharge valve 13 have proximal ends to the valve seat plate 11. It becomes a screwed fixed end, and the front end side becomes a free end, and opens and closes the suction hole 11A and the discharge hole 11B, respectively.

The intake valve 12 opens the valve by the intake stroke in which the piston 16, which will be described later, moves from the top dead center to the bottom dead center, and the valve by the compression stroke in which the piston 16 moves from the bottom dead center to the top dead center. To close it. On the other hand, the discharge valve 13 opens the valve by the compression stroke in which the piston 16, which will be described later, moves from the bottom dead center to the top dead center, and the valve by the suction stroke in which the piston 16 moves from the bottom dead center to the top dead center. To close it.

14 shows the piston rod whose proximal end is rotatably connected to the crankshaft 5 via the bearing 15. The front end side of the piston rod 14 enters the cylinder 7 and reciprocates while swinging the piston 16, which will be described later, provided at the front end thereof in the cylinder 7.

16 is a rocking piston which is slidably installed in the cylinder 7, and the piston 16 reciprocates while swinging in the cylinder 7 as shown in FIG. In addition, the piston 16 partitions the compression chamber 17 between the valve seat plates 11 in the cylinder 7. And the piston 16 is comprised by the piston main body 18, the retainer 19, etc. which are mentioned later.

18 represents the disk-shaped piston body which forms the lower part of the piston 16. The distal end of the piston rod 14 is integrally attached to the center of the lower surface of the piston body 18.

19 is a retainer provided on an upper side of the piston body 18, and the retainer 19 can be attached to or detached from the piston body 18 by using a bolt 20 in order to attach and detach the lip ring 22 to be described later. Is attached.

21 is a groove with a ring provided on the outer circumferential side of the piston 16, and the groove 21 with the ring is a narrow whole opened radially outwardly between the piston body 18 and the retainer 19. The circumference is formed as a recessed groove.

22 is a lip ring serving as a seal member provided on the outer circumferential side of the piston 16. The lip ring 22 seals between the piston 16 and the cylinder 7, and leaks air (pressure) in the compression chamber 17. To prevent. In addition, the lip ring 22 is formed of a resin material (for example, a fluororesin material) that is excellent in wear resistance, flexibility, and self-lubrication property, for example, in order to increase sliding mobility with the cylinder 7. The lip ring 22 is formed of a seal ring having an L cross section.

Here, the lip ring 22 is bent toward the inner side of the attachment portion 22A formed as a flat annular plate and the upper side of the compression chamber 17 side from the outer diameter side of the attachment portion 22A to be expanded into a cup shape. By opening, it is comprised by the lip | rip part 22B which slides in contact with 7A of inner peripheral surfaces of the cylinder 7. As shown in FIG. Then, the attaching portion 22A of the lip ring 22 is inserted between the piston body 18 and the retainer 19 and fixedly attached in a fitted state in the groove 21 to which the ring of the piston 16 is attached. have.

23 is a tank for storing compressed air, which is connected to a discharge port 10A of the cylinder head 8 and stores compressed air discharged from the discharge port 10A. In addition, as shown in FIG. 1, the tank 23 is connected to an external pneumatic device, such as a tablet press, through a blowout port (not shown), and supplies compressed air to the pneumatic device. In addition, the tank 23 is provided with a relief valve (not shown) as a safety device.

24 is a pressure sensor provided in the tank 23, this pressure sensor 24 measures the pressure in the tank 23, and outputs the detection signal according to this pressure toward the control circuit 28 mentioned later.

25 is a power supply unit connected to the electric motor 3, and the power supply unit 25 is provided with a manual switch (not shown) for driving and stopping the electric motor 3, and is used for time measurement as described later. The timer 26, the switching circuit 27 which switches the rotation direction of the electric motor 3, and the control circuit 28 are provided. In addition, the power supply unit 25 is provided with a temperature sensor (not shown) for detecting that the electric motor 3 becomes too high as a safety device.

26 is a timer for measuring time, and this timer 26 measures the time which the electric motor 3 continued to drive in the same rotation direction, for example, and outputs it to the control circuit 28 mentioned later.

27 is a switching circuit for switching the rotational direction of the electric motor 3 in the reverse direction. As shown in FIG. 4, the switching circuit 27 is, for example, a rotary dedicated relay 27A for forward rotation of the output shaft 3A. ) And a reverse rotation relay 27B for reversely rotating the output shaft 3A. Here, the turning dedicated relay 27A connects the U phase, V phase, and W phase of the external three-phase AC power source to the u phase, the v phase, and the w phase of the electric motor 3, respectively. On the other hand, the reverse rotation relay 27B is connected in parallel to the forward rotation relay 27A and simultaneously switches between U phase and V phase among U phases, V phases, and W phases of an external three-phase AC power supply. The U phase, V phase, and W phase of the AC power supply are connected to the v phase, u phase, and w phase of the electric motor 3, respectively. Thereby, when the switching circuit 27 turns ON the forward rotation relay 27A, the switching circuit 27 turns OFF the reverse rotation relay 27B, and rotates the electric motor 3 forward. On the other hand, when the switching circuit 27 turns ON the reverse rotation relay 27B, the forward rotation relay 27A is turned OFF to rotate the electric motor 3 in reverse.

28 is a control circuit as a control means for controlling the drive of the electric motor 3, and this control circuit 28 is constituted by, for example, a microcomputer, a program for controlling the drive of the electric motor 3, and will be described later. The maximum value Pmax of the pressure P, the minimum value Pmin, the fixed time T0 used as the threshold at the time of continuous operation, etc. are previously memorize | stored. In addition, a pressure sensor 24, a timer 26, and a switching circuit 27 are connected to the control circuit 28. The control circuit 28 controls the drive and stop of the electric motor 3 on the basis of the detection signal from the pressure sensor 24 in accordance with a program described later, and at the same time, the timer 26, the switching circuit 27, and the like. To change the rotational direction of the electric motor 3. As a result, the control circuit 28 switches between the case in which the electric motor 3 is rotated forward and the compression unit 6 is compressed and the reverse rotation is performed in the case where the compression unit 6 is compressed.

Next, operation control of the compressor by the control circuit 28 will be described with reference to FIGS. 5 to 7.

First, in FIG. 5, pressure type operation control is performed. The pressure type operation control constantly monitors the inside of the tank 23, and stops the compression operation when the pressure P reaches the predetermined maximum value Pmax, and the pressure P reaches the predetermined minimum value Pmin. When it is finished, it will resume the compression operation.

In this pressure type operation control, first, in step 1, the pressure P is detected using the detection signal of the pressure sensor 24. FIG. Next, in step 2, it is determined whether or not the pressure P is lower than a predetermined maximum value Pmax (for example, Pmax = 0.7 MPa).

And when it determines with "YES" in step 2, it is determined in step 3 whether the pressure P is lower than predetermined minimum value Pmin (for example, Pmin = 0.5 MPa). In addition, when it determines with "YES" in step 3, as mentioned later, a compression operation process is performed in step 4, and a continuing operation process is performed in step 5. As shown to FIG. Thereby, the electric motor 3 rotates forward or reversely, for example at the predetermined rotational speed N0 (for example, N0 = 1450 rpm), and the compression unit 6 performs the compression operation in the forward rotation state, Or the compression operation is performed in the reverse rotation state.

On the other hand, when it determines with "NO" in step 2, the pressure P is more than the maximum value Pmax. For this reason, if the electric motor 3 is a drive state, the rotation direction of the electric motor 3 is memorize | stored in step 6. After that, power feeding to the electric motor 3 is stopped in step 7, and the compression operation of the compressor is stopped.

In addition, when it determines with "NO" in step 3, since the pressure P is between the minimum value Pmin and the maximum value Pmax, it is determined in step 8 whether compression operation is in progress. And when it determines with "YES" in step 8, the compression operation of a compressor is continued in step 5. On the other hand, when it determines with "NO" in step 8, it keeps the operation stop state of a compressor.

In this way, in the pressure type operation control, the compressor is intermittently operated or stopped, so that the pressure P in the tank 23 is controlled to enter between the minimum value Pmin and the maximum value Pmax. In step 9, the processes of steps 1 to 8 are repeatedly executed until the power of the compressor is turned off.

Next, the compression operation process shown in step 4 in FIG. 5 will be described with reference to FIG. 6.

First, when the compression operation process is started, in step 11, it is determined whether or not the rotation direction of the previous electric motor 3 is the forward rotation. And when it determines with "YES" in step 11, it has become forward rotation before the electric motor 3 stopped. For this reason, in step 12, the electric motor 3 is rotated reversely. Specifically, the control circuit 28 turns ON the reverse rotation relay 27B of the switching circuit 27, and turns OFF the forward rotation relay 27A. As a result, the electric motor 3 rotates the output shaft 3A in the reverse direction.

On the other hand, when it was determined as "NO" in step 11, it turned to reverse rotation before the electric motor 3 stopped. For this reason, in step 13, the electric motor 3 is rotated forward. Specifically, the control circuit 28 turns ON the forward rotation relay 27A of the switching circuit 27 and turns OFF the reverse rotation relay 27B. As a result, the electric motor 3 rotates the output shaft 3A toward the forward direction.

Then, after the electric motor 3 is rotated forward or reverse in steps 12 and 13, step 14 is executed and returned.

Next, the continuous operation process shown in step 5 in FIG. 5 will be described with reference to FIG. 7.

First, if the continuous driving process is started, in step 21 whether the time that the electric motor 3 continues to drive in the same rotational direction has passed a predetermined time T0 (for example, T0 = 5 minutes) has passed. Determine.

Specifically, the control circuit 28 resets the timer 26 when the electric motor 3 is switched from the stopped state to the drive state and when the forward rotation and the reverse rotation of the electric motor 3 are switched. As a result, the control circuit 28 detects the continuous drive time T of the electric motor 3 in the same rotational direction by using the signal from the timer 26.

And when it determines with "YES" in step 21, the continued drive time T exceeds the fixed time T0 which becomes a threshold value. For this reason, after memorizing this rotation direction of the electric motor 3 in step 22, the rotation direction of the electric motor 3 is switched in step 23. FIG.

Here, when switching the rotational direction of the electric motor 3, the control circuit 28 temporarily rotates the relay for switching of the switching circuit 27 temporarily in order to prevent a short circuit between the U phase and the V phase, an obstacle due to counter electromotive force, and the like. (27A) and the reverse rotation relay 27B are all turned OFF. After the compressor is stopped only for a predetermined idle time (for example, for a few seconds), only the relay which is different from the previous driving time is turned ON among the forward-only relay 27A and the reverse-only relay 27B. As a result, the electric motor 3 rotates in the reverse direction at the previous forward rotation and in the forward rotation at the previous reverse rotation.

On the other hand, when it determines with "NO" in step 21, the continued drive time T does not exceed the fixed time T0. For this reason, the electric motor 3 keeps driving in the present rotation direction, and returns in step 24. FIG.

The rocking type compressor according to the present embodiment has the configuration as described above. Next, the operation thereof will be described with reference to FIGS. 8 to 15.

First, when the electric motor 3 is rotationally driven, the piston 16 reciprocates while rocking the inside of the cylinder 7 as shown in FIG. As a result, the compressor repeats a suction stroke for sucking air from the suction chamber 9 into the compression chamber 17 and a compression stroke for compressing air in the compression chamber 17 and discharging compressed air into the discharge chamber 10. Compression operation is performed to supply compressed air to an external tank (23).

Here, when the output shaft 3A of the electric motor 3 is rotated forward, as shown in FIG. 8 and FIG. 9, the crankshaft 5 rotates to the arrow A direction. At this time, in the suction stroke, as shown in FIG. 8, the piston 16 descends while inclining toward the bottom dead center from the top dead center. As a result, the intake valve 12 is opened, and external air is sucked into the compression chamber 17.

On the other hand, in the compression stroke (discharge stroke), as shown in FIG. 9, the piston 16 rises inclined in the opposite direction to the time of descent from the bottom dead center to the top dead center. As a result, the air in the compression chamber 17 is compressed, and the discharge valve 13 is opened. For this reason, compressed air is discharged toward the tank 23 via the discharge port 10A.

At this time, the swinging piston 16 reciprocates while swinging in the cylinder 7 in a constant direction. In addition, the lip ring 22 is fixed to the piston 16. For this reason, the both ends of the lip | rip part 22B of the lip ring 22 in the swinging direction of the piston 16 are strongly pressed against the inner peripheral surface 7A of the cylinder 7. In particular, since the pressure in the compression chamber 17 increases in the compression stroke, a large load acts on the piston 16 and the lip ring 22. For this reason, in the both ends of the piston 16 in the rocking direction, the site side with a large displacement until reaching top dead center in the compression stroke becomes the load side, and the site on the opposite side becomes the half load side. As a result, during the forward rotation of the electric motor 3, large wear does not occur in the portion b on the half-load side of the lip ring 22, whereas uneven wear occurs intensively in the portion a on the load side shown in FIG. Tend to.

In contrast, in the present embodiment, when the compressor is intermittently operated and stopped in response to the pressure P in the tank 23 (during intermittent operation), the electric motor 3 is fixed every time the compressor is started. It is set as the structure which switches rotation and reverse rotation. That is, as shown in FIG. 14, when the pressure P in the tank 23 reaches the maximum value Pmax, operation | movement of a compressor is stopped and the pressure P is set to the minimum value using the compressed air in the tank 23. As shown in FIG. When Pmin is reached, operation of the compressor is started.

For example, when the pneumatic equipment connected to the tank 23 uses a large amount of compressed air, and the compressor continues to operate for a long time (for example, several minutes to several hours) (at the time of continuous operation), as shown in FIG. 15, For example, it is set as the structure which switches forward rotation and reverse rotation of the electric motor 3 every fixed time T0 about 5 minutes.

As a result, the output shaft 3A of the electric motor 3 is switched from forward rotation to reverse rotation. When the output shaft 3A of the electric motor 3 is rotated in reverse, the crank shaft 5 rotates in the direction of the arrow B as shown in Figs. 11 and 12. At this time, in the suction stroke, as shown in FIG. 11, the piston 16 is lowered while inclining toward the bottom dead center from the top dead center as in the forward rotation of the electric motor 3. Is inclined in the reverse direction.

On the other hand, in the compression stroke, as shown in FIG. 12, the piston 16 rises while inclining in the opposite direction as it descends toward the top dead center from the bottom dead center. At this time, the piston 16 ascends while inclining in the opposite direction to the forward rotation of the electric motor 3. For this reason, when the electric motor 3 reversely rotates, the load side and the half load side of the piston 16 become a reverse position relationship at the time of forward rotation of the electric motor 3. As a result, since the half load side at the time of forward rotation becomes the load side at the time of reverse rotation of the electric motor 3, partial wear occurs intensively in the site | part b of the load side among the lip rings 22 shown in FIG.

Thereby, wear of the lip ring 22 can be disperse | distributed evenly to the both end sides of the piston 16 in the swinging direction. For this reason, since the abrasion occurs evenly at two points among the entire circumference of the lip part 22B, the life of the lip ring 22 can be extended compared with the case where abrasion occurs at one point like the prior art. . Specifically, compared with the prior art, the life of the lip ring 22 can be extended, for example, from 8000 hours to 15000 hours in intermittent operation, and 6500 hours in continuous operation to about 10,000 hours.

Thus, according to the first embodiment, the control circuit 28 is configured to switch between the case in which the output shaft 3A of the electric motor 3 is rotated forward and the compression operation is performed in the reverse rotation. In the entire circumference of the lip ring 22, the portion a serving as the load side during the forward rotation of the electric motor 3 and the portion b serving as the load side during the reverse rotation of the electric motor 3 can be different. For this reason, since the part pressed strongly by the inner peripheral surface of the cylinder 7 among the lip rings 22 can be disperse | distributed to two points, it can prevent that abrasion generate | occur | produces in one point of the lip ring 22, and the lip ring 22 ) Can extend the life.

Moreover, the control circuit 28 is a structure which switches the rotation direction of the output shaft 3A of the electric motor 3 at the next start after stopping the electric motor 3. For this reason, when the compressor is intermittently operated so that the pressure P of the tank 23 falls between the maximum value Pmax and the minimum value Pmin, the electric motor 3 is stopped with control of stopping and starting the electric motor 3. Switching control of the rotation direction can be performed. For this reason, it is not necessary to provide a new detection means or the like, and switching control of the rotational direction of the electric motor 3 can be performed by using the detection signal of the pressure sensor 24 which is conventionally used.

The control circuit 28 is configured to switch the rotational direction of the output shaft 3A of the electric motor 3 when the electric motor 3 continues to be driven for a predetermined time. For this reason, the load side position of the lip ring 22 can be disperse | distributed to the both sides of the rotation direction of the piston 16 also when a compressor is running continuously without stopping. Therefore, by continuous operation, even when the lip ring 22 tends to be worn by the heat of compression or friction, wear can be prevented from being concentrated at one point of the lip ring 22, and the life of the lip ring 22 can be extended. Can be.

In addition, the control circuit 28 is configured to switch with a predetermined rest time when switching the rotational direction of the output shaft 3A of the electric motor 3. Therefore, even when the rotation direction of the electric motor 3 is changed immediately after the compressor has stopped, for example, the compressor can be driven without causing a short circuit or an obstacle due to counter electromotive force.

Next, Fig. 16 shows a second embodiment of the present invention. The feature of this embodiment is that the electric motor is constituted by a single phase induction motor. In addition, in 2nd Embodiment, the same code | symbol is attached | subjected to the same component as 1st Embodiment mentioned above, and the description is abbreviate | omitted.

31 is an electric motor according to the second embodiment, and the electric motor 31 is constituted by, for example, a condenser starting type single phase induction motor which starts using the condenser 32. As in the first embodiment, the electric motor 31 drives the compression section 6 by rotationally driving the output shaft 31A.

33 is a power supply unit connected to the electric motor 31, and this power supply unit 33 is configured substantially the same as the power supply unit 25 according to the first embodiment, and includes a timer 26, a switching circuit 34, and a control circuit. (35) is provided.

34 is a switching circuit for switching the rotational direction of the electric motor 31, and this switching circuit 34 is provided between the electric motor 31 and a power supply, and starts or stops electric power feeding to the electric motor 31. FIG. It is comprised by the 34 A of power feed switches, and the switching switch 34B which switches and connects one phase of the power supply side with respect to the starting capacitor 32. As shown in FIG.

And the power supply switch 34A is comprised by the magnet type relay etc., for example, and it turns ON and OFF based on the control signal from the control circuit 35 mentioned later. In addition, the changeover switch 34B is also constituted by, for example, a magnet relay, and switches one phase on the power supply side to either one of both ends of the capacitor 32 based on a control signal from the control circuit 35 and connects it. . As a result, the switching switch 34B switches the forward rotation and the reverse rotation of the electric motor 31.

35 is a control circuit as a control means for controlling the drive of the electric motor 31, and this control circuit 35 is constituted by, for example, a microcomputer, and is substantially the same program as the control circuit 28 according to the first embodiment. To work. In addition, a pressure sensor 24, a timer 26, and a switching circuit 34 are connected to the control circuit 35. The control circuit 35 controls the drive and stop of the electric motor 31 on the basis of the detection signal from the pressure sensor 24, and also uses the timer 26, the switching circuit 34, and the like. The rotation direction of 31 is switched.

In this way, also in the second embodiment configured in this manner, the same effects as those of the first embodiment described above can be obtained.

17 and 18 show a third embodiment of the present invention. The characteristic of this embodiment is that it is set as the structure which controls the rotation speed and rotation direction of an electric motor using an inverter.

41 is a power supply unit connected to the electric motor 3, and this power supply unit 41 is configured in substantially the same way as the power supply unit 25 according to the first embodiment, and includes a timer 26, a switching circuit 42, and a control circuit. 43 is provided.

42 is a switching circuit for switching the rotational direction of the electric motor 3, and this switching circuit 42 is provided between the electric motor 3 and a power supply, and starts or stops feeding to the electric motor 3. The power supply switch 42A and the inverter circuit 42B which inverter control the electric current and voltage supplied to the electric motor 3 are comprised.

The feed switch 42A is configured by, for example, a magnet relay, and is turned on and off based on a control signal from the control circuit 43 described later. In addition, the inverter circuit 42B is constituted by a plurality of switching elements (for example, gate turn-off thyristors, insulated gate bipolar transistors, and the like), and each of the electric motors 3 is based on a control signal from the control circuit 43. The current and voltage supplied to the phase are controlled in a variable manner. As a result, the inverter circuit 42B controls the rotation speed of the electric motor 3 variably and switches the forward rotation and the reverse rotation of the electric motor 3.

43 is a control circuit as a control means for controlling the drive of the electric motor 3, and this control circuit 43 is constituted by, for example, a microcomputer or the like, and is substantially the same program as the control circuit 28 according to the first embodiment. To work. The pressure sensor 24, the timer 26, and the switching circuit 42 are connected to the control circuit 43. 18, for example, as shown in FIG. 18, the control circuit 43 variably controls the rotation speed of the electric motor 3 based on the detection signal from the pressure sensor 24, and at the same time, the timer 26, The rotation direction of the electric motor 3 is switched using the switching circuit 42 or the like.

In this way, also in the third embodiment configured in this manner, the same effects as those of the first embodiment described above can be obtained.

In each of the above embodiments, a cooling fan 4 for cooling the compression section 6 is attached to the output shafts 3A and 31A of the electric motors 3 and 31. However, this invention is not limited only to this, For example, when the cooling efficiency of a compression part decreases with reverse rotation of an electric motor, you may make it the structure which provides the cooling fan which drives separately from an electric motor.

In each of the above embodiments, the output shafts 3A and 31A of the electric motors 3 and 31 are directly connected to the crank shaft 5 for reciprocating the piston 16. However, the present invention is not limited to this, but may be configured such that the output shaft and the crank shaft of the electric motor are indirectly connected by using a pulley or the like.

In each of the above embodiments, the suction hole 11A formed in the valve seat plate 11 is opened and closed by using the suction valve 12. However, the present invention is not limited to this, and for example, the crank chamber 2 and the compression chamber 17 are provided in the piston body 52 and the retainer 53 constituting the piston 51 according to the modification shown in FIG. The suction hole 54 which communicates with ()) is formed, and the suction valve 55 which opens and closes this suction hole 54 may be provided in the piston 51.

In each of the above embodiments, an induction motor is used as the electric motors 3 and 31, but other AC motors such as a synchronous motor may be used, or a DC motor may be used.

In addition, in each embodiment, the case where the air is compressed by the swing type compressor has been described as an example. However, the present invention is not limited to this, but may be applied, for example, to compress a refrigerant or the like.

According to the invention of claim 1, since the control means is configured to switch between the case in which the output shaft of the motor is rotated forward and the compression operation is reversed, the case in which the load side is changed at the forward rotation of the motor in the entire circumference of the seal member. The part to be the load side at the time of reverse rotation of the motor can be different. That is, the load side position of the seal member is disposed on one side of the piston swing direction when the motor rotates forward, and is disposed on the other side of the piston swing direction when the motor rotates reversely. For this reason, since the part pressed strongly by the inner peripheral surface of a cylinder among the sealing members can be disperse | distributed to two points, wear concentration can be prevented at one point of a sealing member, and the life of a sealing member can be extended.

According to the invention of claim 2, the control means is configured to switch the rotational direction of the motor output shaft when starting the motor next time. For this reason, when performing intermittent operation of the compressor which stops more than the upper limit of the pressure in an air tank, and starts below a lower limit, for example, switching control of a motor rotation direction can be performed with control of a motor stopping and starting. For this reason, it is not necessary to provide a new detection means etc., and switching control of the rotation direction of a motor can be performed using the signal etc. of the pressure sensor conventionally used.

According to the invention of claim 3, the control means is configured to switch the rotation direction of the motor output shaft when the motor continues to be driven for a predetermined time. For this reason, the position of the lip ring load side can be distributed to both sides of the piston swing direction even when the compressor is continuously operated without stopping, for example. Therefore, wear concentration can be prevented at one point of the lip ring, and the life of the lip ring can be extended.

According to the invention of claim 4, the control means is configured to switch with a predetermined rest time when switching the rotational direction of the motor output shaft. For this reason, the compressor can be driven without causing a short circuit or disturbance due to back electromotive force even when the rotation direction of the motor is changed, for example, immediately after the compressor stops.

Claims (4)

A piston which is connected to a cylinder, an output shaft of the motor, oscillates while swinging in the cylinder, partitions the compression chamber in the cylinder, an annular seal member which is provided on the outer circumferential side of the piston, and seals between the piston and the cylinder, and In the rocking compressor comprising a control means for controlling the drive of the motor, The control means is a swing type compressor, characterized in that it is configured to be switched between the case in which the output shaft of the motor is rotated forward and the compression operation is performed in reverse rotation. The swing type compressor according to claim 1, wherein the control means is configured to switch the rotation direction of the motor output shaft when starting the motor next time after stopping the motor. The swing type compressor according to claim 1 or 2, wherein the control means is configured to switch the rotational direction of the motor output shaft when the motor continues to be driven for a predetermined time. The swing-type compressor according to claim 1 or 2, wherein the control means is configured to switch with a predetermined rest time when switching the rotational direction of the motor output shaft.

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